Fewer
than half of the chemicals most commonly used in commerce have been tested
to determine exposure levels at which they are acutely toxic. Moreover,
testing rarely assesses neurobehavioral functions; the U.S. Environmental
Protection Agency estimates that a test for toxic effects on the developing
brain costs about $150,000.

Of the 201 industrial chemicals known to cause toxic
effects on the human brain, almost half are produced in high volumes.
Several others are on the priority list as major hazards from toxic waste.